Sequence diagrams are one of the most effective ways of organizing the interaction of the objects that are part of a system, to know in a graphic and simple way how the process works as a whole. The good thing about sequence diagrams is that they follow a very clear structure and, due to this, they can be created using various predefined orders. And that is exactly what SDEdit helps us to do.
Generate and edit sequence diagrams
Sequence diagrams are usually generated in UML (Unified Modeling Language), therefore SDEdit supports UML, and when a diagram is saved it can be done so as PDF, (E)PS, SVG, SWF, EMF, GIF, and JPEG, which will surely make distributing the creations a lot easier.
One of the greatest advantages of SDEdit is that it's a free development and that it has been released under the BSD license, even though we have to acknowledge that other proprietary software like Rational Rose, Microsoft Visio or Enterprise Architect are much more complete.
Nevertheless, SDEdit can work perfectly when it comes to creating sequence diagrams in rather small projects or for students.